The proposed marriage amendment to the state Constitution looks like a sure thing on the ballot and a sure thing to pass. But what's not sure is the fallout, which legal experts say could be far greater than assuring opposite sexes at the altar. They speculate its passage might cost some Arkansans their insurance and other employment benefits, which could even dissuade new businesses from locating here. The amendment's language that "legal status for unmarried persons which is identical or substantially similar to marital status shall not be valid or recognized in Arkansas" opens the door to litigation, lawyers say - from both sides of the marriage issue. " 'Substantially similar to marital status.' What does that mean?" asked Lambda Legal Defense Fund regional staff attorney Brian Chase. "I've been a lawyer for 10 years and I don't even know what it means." The state chapter of the ACLU doesn't either, and because of that ambiguity, it's considering challenging the proposed amendment's ballot title. "The average person reading it is going to have a hard time understanding what it's talking about," and its possible impact on civil unions or unmarried heterosexual couples, ACLU state director Rita Sklar said. "Compared to other efforts in other states, [Arkansas's proposal] is much more far-reaching." Sens. Mark Pryor and Blanche Lincoln, whose votes last week killed, for the time being, a move to amend the U.S. Constitution to define marriage as between a man and a woman, said they will vote to amend Arkansas's Constitution. "I have struggled and prayed about the best course of action I can take, on behalf of Arkansans, to ensure the sanctity of marriage exists only between a man and a woman," Pryor said in a news release. A spokesman from Pryor's office said later that the senator also opposes civil unions - which confer limited rights on a same-sex couple - though Pryor doesn't think the amendment would affect them. (The Arkansas Marriage Amendment website, on the other hand, states the Constitution would rule civil unions out as well.) Pryor said he voted against ending a Democratic filibuster on the so-called "Allard Amendment" because doing so would have "opened the flood gates for a slew of other amendments to our Constitution." Lincoln's reason for her "no" vote in Washington and a "yes" vote here: The issue of same-sex marriage is best left to the states. The amendment, if it makes it to the ballot, is expected to pass handily. Opposing it would be a risky political move. John DiPippa, associate dean at the UALR School of Law, said the proposed amendment "seems to prevent the courts in Arkansas, or the legislature for that matter, from enforcing any law that gives equal married status to nonmarried people." State law now defining marriage as the union between a man and a woman includes a clause that says the law does not prevent an employer "from extending benefits to persons who are domestic partners of employees." That allows businesses, both national and home-grown - like Axciom - to offer health and other benefits to domestic partners. (Insurance companies require domestic partners to meet certain requirements to qualify for the coverage.) If the amendment passes, DiPippa said, it would trump state law and "raise significant opportunities to challenge" the status quo, perhaps triggering lawsuits by employees who lose benefits they had previously. If a company that provides domestic partnership benefits - such as Axciom or Comcast or Marriott International, for example - decides not to withdraw that coverage to its Arkansas employees, employees could bring a breach of contract action, DiPippa said. "The court in Arkansas would have to say 'We can't enforce this contract,' " DiPippa said, because that's a "plausible reading of the amendment." And, other lawyers say, that might deter companies from locating in Arkansas. The proposed amendment will also invite lawsuits from anti-gay-marriage groups to make sure the law is interpreted in such a way that it would deprive gay and lesbian couples of the rights that married heterosexuals enjoy, Lambda lawyer Chase noted. "I can guarantee you that there are anti-gay legal groups out there that will file a suit … fighting health insurance coverage," Chase said. It's already happened in New Orleans, where a group sued the city for its domestic partner law, claiming New Orleans had violated the state's ban on gay marriage. They lost, Chase said. The drafters of the amendment don't agree that it will affect private business or do anything other than ensure that only men and women can marry. "It's not our intent to regulate how a private company might choose" to do business, said Martha Adcock, staff attorney for the Arkansas Marriage Amendment Committee, who helped draft the proposal. Adcock agreed that unmarried couples who are state employees might be locked out of future health and other benefits if the amendment passes, but said the General Assembly may be able to do something for them. "Some things may be allowed, some may not." The committee's intention and a court's interpretation, however, are not equal things, Sklar noted. A Colorado amendment that would have disallowed the promotion of same-sex unions was challenged, successfully, on the argument that Constitutions can not make it more difficult for one class of people than another to change the law. Challenging a constitutional amendment sets up far more hoops to jump through than seeking legislative change. The Central Arkansas Library System's contract with United Health now offers domestic partner benefits, director Bobby Roberts said. That makes it perhaps the only quasi-public agency to offer such health benefits. But the odd nature of CALS - a "public body corporate and politic," funded by millage collected in Pulaski and Perry counties, but not a public agency - makes it uncertain how the amendment would affect its insurance policy, though it's "abundantly clear that we have the right to do it" now, Roberts said. Leaving unmarried partners out of health care coverage, Roberts said, is "short sighted." "We ought to extend health care to everyone we can," he said. The more content employees are, the "better off" we are.